Tonometer



FIG. 1 is a top-front-left perspective view of a tonometer;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a left view thereof;

FIG. 5 is a right view thereof;

FIG. 6 is a top view thereof;

FIG. 7 is a bottom view thereof; and,

FIG. 8 is a top-rear-right perspective view of a tonometer.

The broken lines illustrate portions of the tonometer that form no part of the claimed design. 

CLAIM The ornamental design for a tonometer, as shown and described. 